It is proposed to conduct detailed anatomical, cytochemical and biochemical studies of the selected areas of the central nervous system (motor cortex, spinal cord and cerebellum) of neonates born to mothers fed low protein (8 percent protein) and high protein (25 percent protein) diets throughout most of the gestation period with a view to: 1. Establish the comparative sensitivity of these areas of the nervous system to dietary protein deprivation during its critical periods of growth and development. 2. Correlate morphological and anatomical changes at the light and electron microscopic levels with the cytochemical and biochemical alterations in order to arrive at a hypothesis on the mechanism by which the dietary protein deficiency acts to induce the observed changes. 3. Establish a pattern of cytochemical and biochemical changes in nucleic acids and the oxidative and hydrolytic enzymes which may be responsible for the changed course in mental development of the growing organisms. 4. Study the reproductive performance of the monkeys maintained on low protein diets throughout most of their gestation period in terms of studying its effect on the rate of abortions, birth weight deficits, physical dimensions of the neonate, placental weight and effects on conception during the next breeding season. After completing the proposed investigations on the full-term neonates, detailed studies will be undertaken on the fetuses removed from the pregnant mothers after 100, 121 and 142 days of gestation period.